U.S. patent number 7,362,123 [Application Number 11/328,177] was granted by the patent office on 2008-04-22 for inspection apparatus for thin film transistor substrate.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Hyeong-min Ahn, Sergey Antonov, Ho-seok Choi, Jeong-su Ha, Mi-jeong Song, Lemjachine Vassili.
United States Patent |
7,362,123 |
Choi , et al. |
April 22, 2008 |
Inspection apparatus for thin film transistor substrate
Abstract
An inspection apparatus for a TFT substrate formed with a
plurality of pixels, includes a reference substrate being opposite
to and spaced from the TFT substrate and formed with a plurality of
reference patterns corresponding to the pixels, a power supply to
supply power to both a predetermined number of the pixels and the
corresponding reference pattern to form an electric field in a
space between the TFT substrate and the reference substrate, an
electron beam emitter to emit an electron beam to travel from a
first side to a second side of the space, an electron beam detector
to detect the electron beam emitted from the electron beam emitter
and passed through the space, and a controller to determine whether
the TFT substrate includes a defective pixel based on a location of
the electron beam detected by the electron beam detector. Thus, the
inspection apparatus can correctly and quickly inspect the TFT
substrate for defects in a low vacuum state regardless a size of
the TFT substrate.
Inventors: |
Choi; Ho-seok (Suwon-si,
KR), Antonov; Sergey (Suwon-si, KR), Ahn;
Hyeong-min (Yongin-si, KR), Ha; Jeong-su
(Suwon-si, KR), Vassili; Lemjachine (Suwon-si,
KR), Song; Mi-jeong (Suwon-si, KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-si, KR)
|
Family
ID: |
36911699 |
Appl.
No.: |
11/328,177 |
Filed: |
January 10, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060186335 A1 |
Aug 24, 2006 |
|
Foreign Application Priority Data
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|
|
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Jan 31, 2005 [KR] |
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10-2005-0008837 |
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Current U.S.
Class: |
324/754.22;
345/904; 250/306; 324/760.02 |
Current CPC
Class: |
G01N
23/00 (20130101); G09G 3/006 (20130101); G01R
31/307 (20130101); Y10S 345/904 (20130101) |
Current International
Class: |
G01R
31/26 (20060101); G01R 31/302 (20060101) |
Field of
Search: |
;324/770
;250/306-443.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Nguyen; Ha Tran
Assistant Examiner: Chan; Emily Y
Attorney, Agent or Firm: Stanzione & Kim, LLP
Claims
What is claimed is:
1. An inspection apparatus for a TFT substrate formed with a
plurality of pixels, comprising: a reference substrate spaced apart
from the TFT substrate and formed with a plurality of reference
patterns corresponding to the pixels; a power supply to supply
power to both a predetermined number of the plurality of pixels and
at least one of the reference patterns corresponding to the
predetermined number of the plurality of pixels to form an electric
field in a space between the TFT substrate and the reference
substrate; an electron beam emitter to emit an electron beam to
travel from a first side to a second side of the space; an electron
beam detector to detect the electron beam emitted from the electron
beam emitter after passing through the space; and a controller to
determine whether the TFT substrate includes a defective pixel
based on a location of the electron beam detected by the electron
beam detector.
2. The inspection apparatus according to claim 1, wherein: the
electron beam emitter comprises a plurality of micro electron guns
arranged on the first side of the space along a surface of the TFT
substrate to respectively emit electron beams, and a plurality of
focusing units to focus the electron beams emitted from the
corresponding micro electron guns; and the controller controls the
focusing units to focus the electron beams emitted from the
respective micro electron guns to pass between at least one pixel
line formed by a predetermined number of the plurality of pixels of
the TFT substrate and at least one reference line of the reference
patterns corresponding to the pixel line.
3. The inspection apparatus according to claim 2, wherein the
controller controls the power supply to selectively supply power to
the at least one reference line of the plurality of reference
patterns of the reference substrate.
4. The inspection apparatus according to claim 3, wherein the
controller has information about a reference detection location
when the TFT substrate includes no defective pixel, and determines
whether the TFT substrate includes the defective pixel based on a
deviation between the reference detection location and the location
of the electron beam detected by the electron beam detector.
5. The inspection apparatus according to claim 1, further
comprising: a substrate stage on which the TFT substrate is placed
to be opposite to and spaced from the reference substrate; a vacuum
chamber to accommodate the reference substrate, the electron beam
detector and the substrate stage; and a chamber vacuumizer to
vacummize the vacuum chamber according to control of the
controller.
6. An inspection apparatus to identify a defect on a TFT substrate,
comprising: an electron beam emitter to emit at least one electron
beam toward a space between the TFT substrate and a reference
substrate; and an electron beam detector to detect a location of
the at least one electron beam passing through the space and to
detect a defective pixel of the TFT substrate according to the
detected location of the at least one electron beam.
7. The apparatus according to claim 6, further comprising: a power
supply to supply a power to the TFT substrate and the reference
substrate to form an electric field to control the at least one
electron beam to pass through a passage in the space.
8. The inspection apparatus according to claim 7, further
comprising: a controller to select first pixels of the TFT
substrate as a pixel line and second pixels of the reference
substrate as a reference line, wherein the power supply supplies
the power to the first pixels and the second pixels.
9. The inspection apparatus according to claim 7, wherein the
electric field causes the at least one electron beam to be
deflected in the space, and an amount of deflection varies
according to the defective pixel.
10. The inspection apparatus according to claim 6, wherein the TFT
substrate comprises pixel lines having pixels, the reference
substrate comprises reference lines corresponding to the respective
pixel lines, and the electron beam emitter emits the at least one
electron beam along the space between one of the pixel lines and
one of the reference lines corresponding to the one of the pixel
lines.
11. The inspection apparatus according to claim 10, further
comprising: a power supply to supply a power to the one of the
pixel lines to form an electric field to control a passage of the
at least one electron beam.
12. The inspection apparatus according to claim 11, wherein the
location of the at least one electron beam comprises a first
location detected when the one of the pixel lines of the TFT
substrate does not include the defective pixel, and a second
location detected when the one of the pixel lines of the TFT
substrate includes the defective pixel.
13. The inspection apparatus according to claim 12, wherein the
first location and the second location are different from each
other in a direction perpendicular to a surface of the TFT
substrate.
14. The inspection apparatus according to claim 12, further
comprising: a controller to select the defective pixel according to
a difference between the first location and the second
location.
15. The inspection apparatus according to claim 11, wherein the
defective pixel comprises a first number of pixels and a second
number of pixels, the location of at least one electron beam
comprises a first location detected when one of the pixel lines of
the TFT substrate does not include the first and second number of
pixels, and a second location detected when the one of the pixel
lines of the TFT substrate include one of the first number of pixel
and the second number of pixels.
16. The inspection apparatus according to claim 15, further
comprising: a controller to detect one of the first number of
pixels and the second number of pixels according to a difference
between the first location and the second location.
17. The inspection apparatus according to claim 6, further
comprising: at least one focusing unit corresponding to the at
least one electron beam to direct the corresponding electron beam
in the space.
18. The inspection apparatus according to claim 6, further
comprising: a vacuum chamber enclosing the electron beam detector,
the TFT substrate and the reference substrate.
19. The inspection apparatus according to claim 6, wherein two or
more defective pixels of the TFT substrate are identified according
to the detected location of the at least one electron beam.
20. A method of identifying a defect on a TFT substrate using an
electron beam in an inspection apparatus, the method comprising:
supplying an electric field between a pixel line of the TFT
substrate and a reference line of a reference substrate; directing
the electron beam along the electric field; detecting a location of
the electron beam after passing along the electric field through a
space between the TFT substrate and the reference substrate; and
identifying a defect on the TFT substrate based on a deviation of
the detected location from a reference detection location.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit under 35 U.S.C. .sctn.119 from
Korean Patent Application No. 2005-8837, filed on Jan. 31, 2005, in
the Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present general inventive concept relates to an inspection
apparatus for a thin film transistor (TFT) substrate, and more
particularly, to an inspection apparatus capable of inspecting a
defective pixel of a TFT substrate using deflection of an electron
beam.
2. Description of the Related Art
A conventional inspection apparatus for inspecting a TFT substrate
includes an oscilloscope probe controlled to contact the TFT
substrate to analyze a waveform of a signal output by the probe
when the probe is placed in contact with the TFT substrate. It
takes relatively long time when inspecting the TFT substrate with
the conventional inspection apparatus having the oscilloscope probe
to be in contact with the TFT substrate during inspecting because
the oscilloscope probe has to be moved mechanically. Further, the
TFT substrate is likely to be damaged because the oscilloscope
probe directly contacts the TFT substrate.
Accordingly, a contactless inspection apparatus without using the
oscilloscope probe has been developed as an alternative to the
conventional inspection apparatus using the oscilloscope probe in
contact with the TFT substrate. The contactless inspection
apparatus uses a voltage contrast of electron, that is, emits an
electron beam to a TFT substrate and then detects a secondary
electron reflected from the TFT substrate, thereby inspecting
defects on the TFT substrate.
For example, inspection apparatuses detecting the secondary
electron have been disclosed in Japanese Patent First Publication
Nos. 2000-3142 and 1999-265678.
Such a contactless inspection apparatus can detect the secondary
electron beam if a vacuum chamber accommodating the TFT substrate
is maintained in a high vacuum state. That is, when a plurality of
TFT substrates have to be inspected, the vacuum chamber should be
highly vacuumized whenever each TFT substrate is placed inside the
vacuum chamber for inspection. Hence, it takes a relatively long
time to highly vacuumize the vacuum chamber.
Further, because equipment for highly vacuumizing the vacuum
chamber is additionally provided, a size of the contactless
inspection apparatus increases correspondingly.
Also, because the electron beam emitted from an electron gun is
perpendicular to the surface of the TFT substrate, the position of
the electron beam relative to the TFT substrate should be changed
according to the size of the TFT substrate, since the TFT
substrates may have different sizes.
SUMMARY OF THE INVENTION
The present general inventive concept provides an inspection
apparatus capable to correctly and quickly inspect a defect of a
TFT substrate in a low vacuum state regardless of a size of the TFT
substrate.
Additional aspects and/or advantages of the present general
inventive concept will be set forth in part in the description
which follows and, in part, will be obvious from the description,
or may be learned from the practice of the present general
inventive concept.
The foregoing and/or other aspects of the present general inventive
concept may be achieved by providing an inspection apparatus for a
TFT substrate formed with a plurality of pixels, the inspection
apparatus comprising a reference substrate spaced apart from the
TFT substrate and formed with a plurality of reference patterns
corresponding to the pixels, a power supply to supply power to both
a predetermined number of the plurality of pixels and at least one
of the reference patterns corresponding to the predetermined number
of the plurality of pixels to form an electric field in a space
between the TFT substrate and the reference substrate, an electron
beam emitter to emit an electron beam to travel from a first side
to a second side of the space, an electron beam detector to detect
the electron beam emitted from the electron beam emitter after
passing through the space, and a controller to determine whether
the TFT substrate includes a defective pixel based on a detected
location of the electron beam detected by the electron beam
detector.
The electron beam emitter may further include a plurality of micro
electron guns arranged on the first side of the space along a
surface of the TFT substrate to respectively emit electron beams,
and a plurality of focusing units to focus the electron beams
emitted from the corresponding micro electron guns, respectively,
and the controller controls the focusing units to focus the
electron beams emitted from the respective micro electron guns to
pass between one of pixel lines formed by the predetermined number
of the plurality of pixels of the TFT substrate and a line of
reference patterns corresponding to the pixel line.
The controller may control the power supply to selectively supply
power to at least one of the plurality of reference patterns of the
reference substrate.
The controller may have information about a reference detection
location when the TFT substrate includes no defective pixel, and
determines whether the TFT substrate includes the defective pixel
based on a deviation between the reference detection location and
the location of the electron beam detected by the electron beam
detector.
The inspection apparatus may further include a substrate stage on
which the TFT substrate is placed to be opposite to and spaced from
the reference substrate, a vacuum chamber to accommodate the
reference substrate, the electron beam detector and the substrate
stage, and a chamber vacuumizer to vacummize the vacuum chamber 70
according to control of the controller.
The foregoing and other aspects of the present general inventive
concept may also be achieved by providing an inspection apparatus
to identify a defect on a TFT substrate, the inspection apparatus
comprising an electron beam emitter to emit at least one electron
beam toward a space between the TFT substrate and a reference
substrate, and an electron beam detector to detect a location of
the at least one electron beam passing through the space, and to
detect a defective pixel of the TFT substrate according to the
detected location of the at least one electron beam.
The foregoing and/or other aspects of the present general inventive
concept may be achieved by providing a method of identifying a
defect on a TFT substrate using an electron beams in an inspection
apparatus, the method comprising supplying an electric field
between a pixel line of the TFT substrate and a reference line of a
reference substrate, directing the electron beam across the
electric field, detecting a location of the electron beam after
passing through a space between the TFT substrate and the reference
substrate, and identifying a defect on the TFT substrate based on a
deviation of the detected location from a reference detection
position.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects and advantages of the present general
inventive concept will become apparent and more readily appreciated
from the following description of the embodiments, taken in
conjunction with the accompany drawings of which:
FIG. 1 illustrates an inspection apparatus according to an
embodiment of the present general inventive concept;
FIGS. 2 and 3 illustrate an electron beam emitter and an electron
beam detector in the inspection apparatus of FIG. 1;
FIG. 4 illustrates detailed configurations of the inspection
apparatus of FIG. 1; and
FIG. 5 illustrates a method of determining whether a TFT substrate
has a defect using deflection of an electron beam in an inspection
apparatus according to an embodiment of the present general
inventive concept.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the embodiments of the
present general inventive concept, examples of which are
illustrated in the accompanying drawings, wherein like reference
numerals refer to like elements throughout. The embodiments are
described below so as to explain the present general inventive
concept by referring to the figures.
FIG. 1 illustrates an inspection apparatus for a TFT substrate
according to an embodiment of the present general inventive
concept. As illustrated in FIG. 1, the inspection apparatus
comprises a TFT substrate 10, a reference substrate 20, a power
supply 40, an electron beam emitter 30, an electron beam detector
50, and a controller 60.
The reference substrate 20 is opposite to and spaced from the TFT
substrate 10. Here, the reference substrate 20 is formed with a
plurality of reference patterns 21 corresponding to a plurality of
pixels 11 formed on the TFT substrate 10.
The power supply 40 is controlled by the controller 60 to supply
power to both the pixel 11 of the TFT substrate 10 and the
reference pattern 21 of the reference substrate 20. Here, when the
power is supplied from the power supply 40 to the pixel 11 of the
TFT substrate 10 and the reference pattern 21 of the reference
substrate 10, an electric field is formed in a space between the
TFT substrate 10 and the reference substrate 20.
Further, the power supply 40 is controlled by the controller 60 to
supply the power to the reference pattern 21 selected among the
reference patterns on the reference substrate 20. The reference
pattern 21 may be randomly selected from the reference patterns. A
number of the reference patterns may be simultaneously
selected.
The electron beam emitter 30 emits an electron beam to the space
between the TFT substrate 10 and the reference substrate 20,
thereby allowing the electron beam to travel from a first side to a
second side of the space between the TFT substrate 10 and the
reference substrate 20.
FIGS. 2 and 3 illustrate the electron beam emitter 30 and the
electron beam detector 50 of the inspection apparatus of FIG. 1.
Referring to FIGS. 1 through 3, the electron beam emitter 30
comprises a plurality of micro electron guns 31a and 31b, and a
plurality of focusing units 32a and 32b respectively corresponding
to the micro electron guns 31a and 31b.
The micro electron guns 31a and 31b are arranged on first side of
the space to emit electron beams along a surface of the TFT
substrate 10. The electron beam emitted from each micro electron
gun 31a and 31b passes from the first side to the second side of
the space between the TFT substrate 10 and the reference substrate
20, and is detected by the electron beam detector 50. In FIG. 2,
the electron beam emitter 30 comprises four micro electron guns,
but the number of micro electron guns is not limited to four.
Further, the electron beams emitted from the micro electron guns
31a and 31b are focused by the focusing units 32a and 32b, thereby
assigning predetermined scan regions S1 and S2 to the electron guns
31a and 31b, respectively. Referring to FIG. 3, the electron beam
emitted from each micro electron gun 31a or 31b is deflected at a
predetermined angle, and passes between a predetermined pixel line
of the TFT substrate 10 and a reference pattern line of the
reference substrate 20 corresponding to the pixel line. Here, the
respective scan regions S1 and S2 of the electron guns 31a and 31b
are determined according to the deflected angles of the electron
beams, so that the defect of the pixel 11 is inspected
corresponding to each scan region S1 or S2.
The electron beam detector 50 is disposed opposite to the electron
beam emitter 30 with respect to the TFT substrate 10 and the space
which corresponds to a size of the TFT substrate 10 and the
reference substrate 20. According to an embodiment of the present
general inventive concept, the electron beam detector 50 is shaped
like a plate perpendicular to the pixel line of the surface of the
TFT substrate 10.
Further, the electron beam detector 50 includes a plurality of
detectors 51a, 51b, 51c and 51d formed thereon to detect the
electron beams emitted from the respective micro electron guns 31a
and 31b.
The controller 60 determines whether the pixel 11 of the TFT
substrate 10 has one of more defects, based on a detected location
of the electron beam detected by the electron beam detector 50.
As shown in FIG. 4, the controller 60 comprises a beam control unit
62, a power control unit 63, and a main control unit 61.
The beam control unit 62 is associated with the main control unit
61 to control each micro electron gun 31a or 31b of the electron
beam emitter 30 to emit the electron beam and each focusing unit
32a or 32b to deflect the electron beam at a predetermined
angle.
The power control unit 63 is associated with the main control unit
61 to control the power supply 40. Thus, it is possible to control
the voltage and/or the supply of the power for the TFT substrate 10
and the reference substrate 20. Further, the power control unit 63
controls the power supply 40 to supply the power to at least one of
the reference patterns 21 formed on the reference substrate 20.
The main control unit 61 determines whether the TFT substrate 10
has one or more defects, based on the detected location of the
electron beam detected by the electron beam detector 50.
Hereinafter, it will be described how the main control unit 61 is
associated with the beam control unit 62 and the power control unit
63 and determines whether the pixel 11 of the TFT substrate 10 has
the one or more defects.
First, the main control unit 61 selects a predetermined pixel line
of the TFT substrate 10. Here, the main control unit 61 can select
a plurality of pixel lines corresponding to the scan regions S1 and
S2 of the respective micro electron guns 31a and 31b so that the
selected pixel lines corresponding to the micro electron guns 31a
and 31b can be inspected at the same time. Further, the main
control unit 61 can selectively inspect one or more pixel
lines.
Then, information about the one or more pixel lines selected by the
main control unit 61 is transmitted to the power control unit 63
and the beam control unit 62.
The beam control unit 62 controls the micro electron guns 31a and
31b and the focusing units 32a and 32b so that the electron beam
passes through the space between the pixel line selected by the
main control unit 61 and the reference pattern line corresponding
to the selected pixel line.
Further, the power control unit 63 controls the power supply 40 to
supply the power to the reference pattern line corresponding to the
pixel line selected by the main control unit 61. At this time, the
power control unit 63 can control the power supply 40 to supply the
power to all pixels 11 of the TFT substrate 10 while the TFT
substrate 10 is inspected. Thus, an electric field is applied
between the reference substrate 20 and the TFT substrate 10. Here,
when the power is not supplied to the reference pattern lines
corresponding to the pixel lines unselected by the main control
unit 61, the electric field is not formed between the unselected
pixel line and the reference pattern line corresponding
thereto.
In the meantime, while passing through the space between the TFT
substrate 10 and the reference substrate 20, the electron beams
emitted from the micro electron guns 31a and 31b are deflected by
the electric fields formed in the space. Then, the deflected
electron beam is detected at a predetermined location of the
electron beam detector 50.
Then, the main control unit 61 determines whether the corresponding
pixel line has a defective pixel 11, based on the detected location
of the electron beam detected by the electron beam detector 50.
For example, as illustrated in FIG. 5 the main control unit 61
determines whether the corresponding pixel line has a defective
pixel 11, based on the detected location of the deflected electron
beam by the electron beam detector 50.
First, the main control unit 61 previously stores information about
the location of the electron beam detected by the electron beam
detector 50 when the selected pixel line has no defective pixel,
i.e., information about a reference detection location. Here, the
reference detecting location can be obtained by experiments or
calculated based on the electric field, the electrons speed, the
distance between the inspected pixel 11 and the electron beam
detector 50, etc.
Further, the main control unit 61 compares the reference detection
location with the actual detected location of the electron beam
passing through the selected pixel line and detected by the
electron beam detector 50. The main control unit 61 determines that
the selected pixel line has no defective pixel when the detected
location is matched with the reference detection location (or
belongs to a predetermined detecting area).
On the other hand, the main control unit 61 determines that the
selected pixel line has at least one defective pixel 11 when the
detected location is deviated from the reference detection
location.
Through the foregoing method, the main control unit 61 detects the
pixel line having the defective pixel 11 among all pixel lines of
the TFT substrate 10.
Meanwhile, the main control unit 61 detects the defective pixel 11
from the pixel line, as follows. Here, the pixel line having the
defective pixel 11 will be called a defective pixel line.
The main control unit 61 selects the reference pattern 21 to
receive the power in the reference pattern line of the reference
substrate 20 corresponding to the defective pixel line, based on
the detected location of the electron beam passing through the
defective pixel line. For example, the main control unit 61
determines an approximate location of the defective pixel 11 in the
defective pixel line based on the deviation of the detected
location from the reference detecting location. Here, the location
of the defective pixel 11 in the defective pixel line is obtained
by experiments or calculated based on the electric field, the
electron beam deflection, etc. For example, the reference pixel
line can be divided into two pixel groups that belong to the
electron beam emitter side and the electron beam detector side
based on the deviation of the detected location from the reference
detection location.
When the main control unit 61 determines that the defective pixel
11 is located in the pixel group of the electron beam emitter side
on the basis of the deviated degree of the detected location from
the reference detecting location, the main control unit 61 informs
the power control unit 63 and the beam control unit 62 that the
defective pixel 11 is located in the pixel group of the electron
beam emitter side.
At this time, the power control unit 63 supplies the power to only
the reference pattern 21 corresponding to the pixel 11 that belongs
to the pixel group determined by the main control unit 61. Further,
the beam control unit 62 controls the electron beam emitter 30 to
pass the electron beam through the pixel group determined by the
main control unit 61.
Here, the main control unit 61 has previously stored information
about the location of the electron beam detected by the electron
beam detector 50 when the determined pixel group includes no
defective pixel 11, i.e., information about the reference detection
location for the determined pixel group. Here, the reference
detecting location for the determined pixel group can be obtained
by experiments or calculated on the basis of the electric field,
the electron beam deflection, etc.
Further, the main control unit 61 compares the reference detection
location for the determined pixel group with the detected location
of the electron beam passing through the determined pixel group and
detected by the electron beam detector 50. Then the main control
unit 61 determines what pixel of the determined pixel group has
defects according to whether the detected location is matched with
the reference detection location for the determined pixel group (or
belongs to a predetermined detecting area).
Here, the main control unit 61 determines an approximate location
of the defective pixel 11 in the determined pixel group based on
the basis of the deviation of the detected location from the
reference detection location for the determined pixel group,
thereby finally detecting the defective pixel 11.
Referring to FIGS. 1 and 4, the inspection apparatus comprises a
substrate stage 71 on which the TFT substrate 10 is put to be
opposite to and spaced from the reference substrate 20, a vacuum
chamber 70 to accommodate the reference substrate 20, the electron
beam detector 50 and the substrate stage 71, and a chamber
vacuumizer 72 to vacummize the vacuum chamber 70 according to
control of the controller 60.
While the TFT substrate 10 is inspected, the controller 60 controls
the chamber vacuumizer 72 to maintain the vacuum chamber 70 in a
lower vacuum state than that of the conventional inspection
apparatus. Contrary to the conventional inspection apparatus that
requires the vacuum chamber to have a higher vacuum state for more
correctly detecting the secondary electrons, the inspection
apparatus according to an embodiment of the present general
inventive concept correctly determines whether the TFT substrate 10
is defective or not based on the electron beam deflection even
though the vacuum chamber 70 thereof is in a lower vacuum state
than that of the conventional inspection apparatus. As the vacuum
chamber 70 is maintained in the lower vacuum state, it is possible
to reduce the time taken to highly vaccumize the vacuum chamber 70,
and simplify the configurations of the chamber vacuumizer 72.
Because electron beams are easily deflected by the focusing units
to propagate along different lines in the space between the TFT
substrate 10 and the reference substrate 20, substrates with
different sizes can be easily inspected without additional
adjustments of the electron beam emitter.
In the foregoing embodiment, the defective pixel line may be
divided into two or more pixel groups so as to more accurately
detect the defective pixel from the defective pixel line.
Alternatively, various algorithms using multiple experiments or the
minimum measurement based on calculation considering the electric
field and the electron beam deflection may be used in detecting the
position of defective pixel.
As described above, the present general inventive concept provides
an inspection apparatus capable of correctly and quickly inspecting
a TFT substrate for defects in a low vacuum state regardless the
size of the TFT substrate.
Although a few embodiments of the present general inventive concept
have been shown and described, it will be appreciated by those
skilled in the art that changes may be made in these embodiments
without departing from the principles and spirit of the general
inventive concept, the scope of which is defined in the appended
claims and their equivalents.
* * * * *